When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 02 CLK 430 and the soft top has stopped opening. It will close electronically when manually opened but will not open. Took it to the dealership for a diagnosis and they said fault codes for the soft top limit switch returned. The recommendation is to replace the soft top assembly switch ( part a208-820-23-10) which they quoted as $885 CAD to repair., as the soft top bow limit switch is malfunctioning and losing its position. Has anyone else had this issue? Any help would be greatly appreciated.
Almost every issue with that switch has been due to it's attachment onto the left rear bow cylinder becoming unclipped, such that it no longer properly actuates, as the cylinder rod raises or lowers the bow.
Last edited by Serndipity; 06-27-2018 at 08:41 PM.
The purpose of the switch is to tell the soft top controller whether the rear bow has been fully raised or lowered. Thereafter, the controller will continue opening or closing the top.
As shown above, the rear bow up/down position switch is attached onto the left bow cylinder. It also has a sliding extension that attaches to the end of the cylinder's rod. As the cylinder rod extends or retracts, the switch changeover contacts toggle,
As shown above, quite often the problem is just that the switch's attachment at the end of the cylinder rod has become unclipped, When this occurs, the switch will no longer properly actuate, as the cylinder rod raises or lowers the bow.
In so, the 'push on' U clip can usually be reattached at $0 expense. Note: To prevent further occurrences, some DIYers added supplementary wire twist ties etc. to secure the U clip.
As usually the case, the $885 CAD dealer quote you received was to fix the problem with a new switch and labor. Note: In order to replace the entire switch, removal of the rear seat and side panel is required.
Last edited by Serndipity; 06-28-2018 at 11:46 AM.
I have replaced all my CLK430 W208 soft top cylinders and my rollbar valve. My lift cylinder limit switch had the two "nubs" that go into the cylinder worn down (sorry no pictures of this yet) so Klaus @Top Hydraulics suggested that I use a zip tie to tie the switch to the cylinder body. I did that, and the switch is now tightly on the cylinder (and the extension clip is firmly on the end of the cylinder rod). I am having some other issues with the top operation unrelated to hydraulics that I am troubleshooting as time permits. Once I get the top working properly, I'll post on a separate thread with pictures and videos. I can say that doing the seven cylinders and the rollbar valve block is not that difficult, especially if you have two people to help raise the top frame to get you better access to some of the cylinders. The two most difficult cylinders to replace were the left and right lift cylinders because of the bolt/nut pivot arrangement and the lack of space to get wrenches in.
Last edited by CLKGeek; 10-23-2019 at 02:05 AM.
Reason: Added spacing between pictures.
I have replaced all my CLK430 W208 soft top cylinders and my rollbar valve. My lift cylinder limit switch had the two "nubs" that go into the cylinder worn down (sorry no pictures of this yet) so Klaus @Top Hydraulics suggested that I use a zip tie to tie the switch to the cylinder body. I did that, and the switch is now tightly on the cylinder (and the extension clip is firmly on the end of the cylinder rod). I am having some other issues with the top operation unrelated to hydraulics that I am troubleshooting as time permits. Once I get the top working properly, I'll post on a separate thread with pictures and videos. I can say that doing the seven cylinders and the rollbar valve block is not that difficult, especially if you have two people to help raise the top frame to get you better access to some of the cylinders. The two most difficult cylinders to replace were the left and right lift cylinders because of the bolt/nut pivot arrangement and the lack of space to get wrenches in.
After replacing hydraulic cylinders and then finding that the power roof does not operate properly, the culprit is often that one or more of your position/limit switch settings is no longer set properly (e.g. no longer synchronized to what the controller expects to see during it's programed operating sequence).
At this time, my suggestion would be to open and close the roof manually, which will actuate (trigger) the switches back into their required positions that match the sequence of what the controller requires to operate the roof.
The instructions to manually operate the roof are explained in detail in the 'practical hints' section of your owners manual.
After you complete this procedure, don't forget to turn the screw that reduced the hydraulic system pressure, back to restore full pressure.
Last edited by Serndipity; 10-23-2019 at 12:25 PM.
After replacing hydraulic cylinders and then finding that the power roof does not operate properly, the culprit is often that one or more of your position/limit switch settings is no longer set properly (e.g. no longer synchronized to what the controller expects to see during it's programed operating sequence).
At this time, my suggestion would be to open and close the roof manually, which will actuate (trigger) the switches back into their required positions that match the sequence of what the controller requires to operate the roof.
The instructions to manually operate the roof are explained in detail in the 'practical hints' section of your owners manual.
After you complete this procedure, don't forget to turn the screw that reduced the hydraulic system pressure, back to restore full pressure.
I have been doing manual open/close but that hasn't helped. My next step is to unplug the N52 connector and monitor the state of all the switches as I manually open and close the top and make sure I see the expected switch states at different positions of the top and various latches.
Side note #1: Charging $2600 for two multi-pin connectors, a 50 pin cable and a small box with banana jacks seems like someone is making a lot of money for a whole lot of nothing. I wonder if there would be a (small?) market for aftermarket diagnostic tools that are a fraction of the cost?
Side note #2: Can the states of the various top/latch switches be read via the OBD II connector or only via the CAN bus? If the latter, has anyone reverse engineered the CAN bus protocol to allow talking to the N52 controller without buying a SDS (again for a ridiculous amount of money)? Or is there a less expensive alternative to a complete SDS that can be used just to read various sensors in the car?
Side note #1: Charging $2600 for two multi-pin connectors, a 50 pin cable and a small box with banana jacks seems like someone is making a lot of money for a whole lot of nothing.
I wound up buying a used N52 soft top controller with matching cable harness connector on eBay for $78 (see post #6) which I'll use to make up a test harness to make testing the switches and feeding manual switch states into the controller much easier than trying to poke wires and test leads into the existing connector on the car harness. My plan is to have a breakout box with LEDs that show the state of each switch as well as the ability to route the N52 switch controller input for each switch individually to the actual switch on the car (normal operation), not connected to anything, and connected to a switch on the breakout box where I can manually control the state of that switch. The description of this gadget is much more complicated than the gadget itself Given that I don't know anything about the characteristics of the N52 controller inputs, all the switch sense circuits will be buffered so as not to load down the inputs on the controller and the output of the buffers will drive the LEDs. Perhaps overkill, and when I open up the eBay N52 controller and inspect the input circuitry I may decide to forgo buffering. In either case, it's not a major project to add buffering. Plus, for $78 not only do I get the connectors I need but also a very nice aluminum enclosure to mount the circuitry.
Once I design and verify that this works, I'll post the schematic so that anyone can build their own.
Used N52 soft top controller from eBay with matching cable harness connector
Last edited by CLKGeek; 10-24-2019 at 04:06 PM.
Reason: Added note about enlocusre
I have replaced all my CLK430 W208 soft top cylinders and my rollbar valve. My lift cylinder limit switch had the two "nubs" that go into the cylinder worn down (sorry no pictures of this yet) so Klaus @Top Hydraulics suggested that I use a zip tie to tie the switch to the cylinder body. I did that, and the switch is now tightly on the cylinder (and the extension clip is firmly on the end of the cylinder rod). I am having some other issues with the top operation unrelated to hydraulics that I am troubleshooting as time permits. Once I get the top working properly, I'll post on a separate thread with pictures and videos. I can say that doing the seven cylinders and the rollbar valve block is not that difficult, especially if you have two people to help raise the top frame to get you better access to some of the cylinders. The two most difficult cylinders to replace were the left and right lift cylinders because of the bolt/nut pivot arrangement and the lack of space to get wrenches in.
As you mentioned, replacing the lift cylinders is awkward, specially the left side (drivers side), due to the proximity with the rear bow tension cylinder and several switches in that area (e.g. S84/15 and S84/5).
In my initial reply, I suggested that you manually open and close the roof, because that would reset of all the position/limit switches, such that during power roof operation, as the controller cyclically analyzes the positions of the limit and operating switches, it will appropriately switch the valve block's solenoid valves, to actuate the hydraulic cylinders and successfully open or close the roof. That is frequently the solution, where substantial of sections of the roof were manipulated in repair.
You then replied....."I have been doing manual open/close but that hasn't helped. My next step is to unplug the N52 connector and monitor the state of all the switches as I manually open and close the top and make sure I see the expected switch states at different positions of the top and various latches.".
Since there was no joy after the re-synchronization process, have you considered that just the triggering mechanism (e.g. mechanically) for either S84/15 or S84/5 was thrown off when you replaced the left lift cylinder?
As example:
The body of the S84/15 rear bow up/down position/limit switch is attached to the left side rear bow up/down cylinder (not the the left side lift cylinder as you stated) and triggers via a sliding arm that attaches to the end of the cylinder's rod (e.g. with a cir-clip). As the moving arm extends or retracts , the controller uses the status to setup and either lower or raise the rear bow (e.g. depends on whether the top is being opened or lowered).
More specifically, S84/13 consists of 2 separate switches (e.g. S84/3s1 and S84/13s2), each with normally open contacts.
When the rear bow is in the down position, the resistance (measured between ground and N52 pin 11), will be 0 - 5 ohms (e.g. switched to ground).
When the rear bow is in the up position, the resistance (measured between ground and N52 pin 13), will be 0 - 5 ohms (e.g. switched to ground).
By virtue of the moving arm and use of 2 separate internal switches, S84/13 must 'fully toggle', indicating that the bow is either up or down. Neither of the switch contacts are closed when the top is in an intermediate position (over a certain range).
Most of the issues with the S84/13 switch have been due to the cir-clip becoming unfastened from the cylinder rod or the switch becoming unfastened from the cylinder body.
Note: The mechanical triggering of the various position/limit switches vary (e.g. pull in/out , tilt, linear contact) and just being off a couple of millimeters, prevents actualization.
06-27-2018, 05:12 PM
Left lift cylinder limit switch
Given that I don't know anything about the characteristics of the N52 controller inputs, all the switch sense circuits will be buffered so as not to load down the inputs on the controller and the output of the buffers will drive the LEDs. Perhaps overkill, and when I open up the eBay N52 controller and inspect the input circuitry I may decide to forgo buffering. In either case, it's not a major project to add buffering. Plus, for $78 not only do I get the connectors I need but also a very nice aluminum enclosure to mount the circuitry.
